45 lines
1.4 KiB
HLSL
45 lines
1.4 KiB
HLSL
/* Copyright (c) 2024, Sascha Willems
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 the "License";
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#define HASHSCALE3 float3(443.897, 441.423, 437.195)
|
|
#define STARFREQUENCY 0.01
|
|
|
|
// Hash function by Dave Hoskins (https://www.shadertoy.com/view/4djSRW)
|
|
float hash33(float3 p3)
|
|
{
|
|
p3 = frac(p3 * HASHSCALE3);
|
|
p3 += dot(p3, p3.yxz + float3(19.19, 19.19, 19.19));
|
|
return frac((p3.x + p3.y) * p3.z + (p3.x + p3.z) * p3.y + (p3.y + p3.z) * p3.x);
|
|
}
|
|
|
|
float3 starField(float3 pos)
|
|
{
|
|
float3 color = float3(0.0, 0.0, 0.0);
|
|
float threshhold = (1.0 - STARFREQUENCY);
|
|
float rnd = hash33(pos);
|
|
if (rnd >= threshhold)
|
|
{
|
|
float starCol = pow((rnd - threshhold) / (1.0 - threshhold), 16.0);
|
|
color += starCol.xxx;
|
|
}
|
|
return color;
|
|
}
|
|
|
|
float4 main([[vk::location(0)]] float3 inUVW : TEXCOORD0) : SV_TARGET
|
|
{
|
|
return float4(starField(inUVW), 1.0);
|
|
} |